The NASA, Aerojet Rocketdyne, and Syncom Space Services team at Stennis Space Center in Mississippi have conducted a “make-up” hot-fire test of a development RS-25 engine (E0528) on Friday. The test was deemed to be for the full duration of 650 seconds, as required, following problems with the A-1 test stand facility that resulted in a mid-July test being cut short.
Test 901-1016 on July 14 was planned to last 650 seconds, exercising Engine 0528 at different throttle settings to achieve a series of test objectives. However, the test was abruptly terminated with the engine commanded to shutdown approximately 193 seconds after ignition.
The problem was not the result of engine problems, but with the test facility itself. Syncom Space Services is the prime contractor for Stennis facilities and operations.
“Initiated at 5:57 p.m. (CST), a minor issue with the test stand triggered an early shutdown 193 seconds into the test, scheduled for 650 seconds. Facility control systems in place responded properly by shutting down the test in an orderly fashion,” NASA said in a media release after the July 14 test.
Earlier this week, answering a question in a NASA Advisory Council (NAC) Human Exploration and Operations Committee meeting, NASA Exploration Systems Development Deputy Associate Administrator Bill Hill gave a little more detail on what happened.
“What we had during that test was…[for] the industrial water that feeds and cools the flame trench we had a low-pressure indication, indicating that we had a [water] leak somewhere, so we shut down the test,” he explained.
A separate, unrelated facility issue also aborted the countdown leading up to engine ignition, delaying start of the test while engine and facility systems were recycled.
No issues were noted with the engine coming out of the abbreviated hot-fire and Hill noted in his presentation to the NAC HEO Committee that a readiness review for the re-test was completed last Friday, July 22.
Work to fix the facility issues that stopped the original test were completed early this week.
Even with the addition of this re-test, no impact to the RS-25 work schedule or the overall Space Launch System (SLS) development schedule is expected.
Most of the scheduling impacts appear to be focused on Orion and other funding elements, whereas the propulsion side of the rocket continues to have good margins for the current EM-1 launch date target.
Although the test was cut short, no problems were noted with the engine hardware or software and several test objectives were achieved in the hot-fire time accumulated.
Friday’s re-test, designated 901-1017, was not an exact repeat; although it was still planned to last 650 seconds and cover the remaining objectives of the original 1016 test, the test profile was adjusted to account for the different set of test objectives.
Ignition occurred at 2:10pm local time and ran for the planned 650 seconds.
A primary objective of the test series with E0528 is to verify the new engine control system and new engine controller for the RS-25.
Other test objectives for the original test included testing engine start conditions in the center of the “start box,” running the engine for extended durations at different power levels, and doing a “green-run” of a fuel flow sensor.
The next RS-25 hot-fire test at Stennis to continue the test series with E0528 is still planned for August 18.
After that, flight engine controller hardware will be tested on the engine in three subsequent hot-fire tests planned to start in the Fall and conclude before the end of the year.
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